如何在 Jython/Java 代码中提供 python 包路径

Question

我从这个链接中获取了一个书面样本来编写我的Python + Java集成代码。

http://www.jython.org/jythonbook/en/1.0/JythonAndJavaIntegration.html

代码如下所示。

package org.jython.book.interfaces;
import org.jython.book.interfaces.JythonObjectFactory;
import org.python.core.Py;
import org.python.core.PyString;
import org.python.core.PySystemState;
public class Main {
    public static void main(String args[]) {
        String projDir = System.getProperty("user.dir");
        String rootPath = projDir + "/src/org/jython/book/interfaces/";
        String modulesDir = projDir + "/src/org/jython/book/interfaces/";
        System.out.println("Project dir: " + projDir);
        PySystemState sysSt = Py.getSystemState();
        JythonObjectFactory factory = new JythonObjectFactory(sysSt, BuildingType.class, "Building", "Building");
        BuildingType building = (BuildingType) factory.createObject();
        building.setBuildingName("BUIDING-A");
        building.setBuildingAddress("100 MAIN ST.");
        building.setBuildingId(1);
        System.out.println(building.getBuildingId() + " " +
            building.getBuildingName() + " " +
            building.getBuildingAddress());
    }
}

当我运行此代码时，它会抛出一个错误，指出它没有找到 python 模块。我将.py和.pyc文件保存在作为"modulesDir"提供的路径下。

文献说"the requested module must be contained somewhere on the sys.path";但是，我不明白如何从这个Java程序设置它。有人可以提供一些帮助吗？

Project dir: /Users/eclipsews/PythonJava
Exception in thread "main" ImportError: No module named Building

Answer 1

嗨，

找到了这个问题的答案！

添加了 PySystemState.initialize 方法，其中我显式提供"python.path"属性，该属性初始化为我的项目路径，其中 python 模块可用。

private static Properties setDefaultPythonPath(Properties props) {
    String pythonPathProp = props.getProperty("python.path");
    String new_value;
    if (pythonPathProp == null) {
        new_value  = System.getProperty("user.dir") + "/src/org/jython/book/interfaces/";       
    }
    props.setProperty("python.path", new_value);
    return props;
}
Properties props = setDefaultPythonPath(System.getProperties());
PySystemState.initialize( System.getProperties(), props, null );

这将生成正确的输出，如下所示：

module=<module 'Building' from '/Users/eclipsews/PythonJava/src/org/jython/book/interfaces/Building$py.class'>,class=<class 'Building.Buildin
g'>
1 BUIDING-A 100 MAIN ST.